1. Field of the Invention
The present invention relates to an iron golf club (hereinafter, simply referred to as a “cavity iron”) having a cavity portion on the rear surface side of the face portion and a golf club set, and more specifically, to a cavity iron golf club provided on a surface of a sole portion defining the cavity portion with a groove for adjusting a thickness of the face portion while increasing an effective face length and a golf club set having such a golf club.
2. Description of the Background Art
Conventionally, a cavity iron golf club is known in which a sole portion is formed in an undercut-shape in order to achieve weight reduction and to position the centroid position toward the rear side of the face, i.e. deepening the centroid. This type of iron golf club head is disclosed, for instance, in Japanese Utility Model Publication No. 5-27951.
FIG. 23 is a cross sectional view of an iron golf club head disclosed in Japanese Utility Model Publication No. 5-27951.
As shown in FIG. 23, a head portion 1 includes a cavity portion 2, a face portion 3 having a ball hitting surface, and a sole portion 4. An undercut surface 5 is formed by slanting the surface of sole portion 4 defining cavity portion 2. In this manner, by forming undercut surface 5, the centroid depth can be deepened while achieving weight reduction of head portion 1.
In the above document, however, no mention is made of the thickness of face portion 3, and the thickness of face portion 3 is uniform as shown in FIG. 23.
The cavity iron of the type shown in FIG. 23 has excellent directivity of the hit ball, but also has the problem that improvement in carry cannot be achieved.
In addition, since the thickness of face portion 3 is uniform, the cavity iron of FIG. 23 had the problem of significant reduction in the carry in the case of an offset strike where a golf ball is struck at a location other than the sweet spot.